Percentage Difference Calculator

The percentage difference is how far apart two numbers are, as a percent of their average: the gap divided by the average, times 100. The percent difference between 80 and 100 is 20 / 90 × 100 = 22.2%. It compares two values on equal terms, with neither one treated as the original.

Subtract the smaller number from the larger one, add the two numbers and halve the sum to get the average, divide the gap by the average, and multiply by 100. For 45 and 55: 55 − 45 = 10, (45 + 55) / 2 = 50, 10 / 50 = 0.2, and 0.2 × 100 = 20%.

With the values in A1 and B1, type =ABS(A1-B1)/AVERAGE(A1,B1) in another cell and format the cell as a percentage. For 45 and 55 it returns 20%. Google Sheets uses the same formula. For percent change use =(B1-A1)/A1.

Percent change uses the starting value as the base and has a direction: 45 to 55 is up 22.22%, and 55 to 45 is down 18.18%. Percent difference uses the average as the base and has no direction: both pairs differ by 20%. Use change for before and after, and difference for two values on equal footing.

Choose percent change when one value came first, such as last year's sales and this year's. Choose percent difference when neither value is the reference, such as two stores' prices or two measurements of the same thing. In percent change mode the calculator also shows the percent difference of the same two values, so you can compare them.

Subtract the old value from the new value, divide by the old value and multiply by 100. From 80 to 100 the change is 20, and 20 / 80 × 100 = 25%. Pick "Percent change" in the calculator, or use the percentage calculator, which also handles negative numbers.

Subtract one percentage from the other to get the gap in percentage points: 50% and 40% are 10 points apart. To say how much larger one is than the other in relative terms, use percent change with the other value as the base: 50% is 25% larger than 40% (10 / 40 × 100), and 40% is 20% smaller than 50% (10 / 50 × 100). The percent difference of 22.2% (10 / 45 × 100) only says how far apart the two values are relative to their average.

No, it takes values from zero up. The average of a positive and a negative number can come out near zero, which would make the percentage huge and meaningless. For quantities that can be negative, such as profit and loss, use the percent change in the percentage calculator.

No. The gap is taken without its sign and the average is never negative here, so the result is 0% or more. Only percent change can be negative: it shows a decrease. A percent difference of 0% means the two values are equal.

Yes, up to 200%. Compare 10 and 90: the gap is 80, the average is 50, and 80 / 50 × 100 = 160%. The ceiling of 200% is reached when one of the values is 0. The larger the gap compared with the average, the higher the percentage.

Percent difference still works: any positive number against 0 gives 200%, because the gap equals twice the average. Percent change does not work when the starting value is 0, since you cannot divide by zero. Two zeros give no result, because their average is 0.

It takes two numbers, finds the gap between them and their average, divides the gap by the average and shows the result as a percent. This one also shows the steps, and its percent change mode gives the percent change from the first number to the second next to the percent difference.

The formula has several steps and it is easy to divide by the wrong number. A calculator avoids that and shows each step. In percent change mode it also shows the percent difference of the same two numbers, which makes the point that they are different figures, something many people mix up.

Shoppers compare the prices of the same product at two stores. Teachers compare the scores of two classes. Scientists compare two measurements of one quantity made by different methods, such as 10.2 and 9.95 m/s² for the acceleration of gravity, which differ by 2.5%. Analysts compare two groups of equal standing.

Percent error compares a measured value with an accepted one, and it divides by the accepted value: |accepted − measured| / accepted × 100. Percent difference compares two measured values and divides by their average. Use percent error when one number is the known right answer.